Green synthesis of nano cobalt ferrite for the enhancement of structural, morphological, magnetic, electrical, and optical properties

Abstract

A green synthesis method was employed to obtain cobalt ferrite nanoparticles (NPs) from orange extract in three different volumes (100, 150, and 200 mL). This provides an eco-friendly and convenient method to produce nanoparticles. The phytochemicals present in the extract act as reducing and stabilizing agents in the formation of cobalt ferrite nanoparticles. The orange extract has proved to be effective in modifying the crystallite size; a higher extract volume of orange juice produced smaller-sized crystallite nanoparticles. X-ray diffraction (XRD), simultaneous thermal analysis (STA), UV-vis absorption spectroscopy, scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM) were used to characterize the effects of varying amounts of chelating agents on the morphological, structural, and optical characteristics of the produced CoFe₂O₄. FTIR analysis proved the synthesized samples' spinel structure and the force constant for the Fe–O bond was calculated to be 262.398 N m⁻¹ and for the Co–O bond was 156.047 N m⁻¹. The distribution of chemical components among the particles with varying quantities of O, Fe, and Co was determined using energy-dispersive X-ray (EDX) spectroscopy. According to the XRD analysis, the NPs' crystallite sizes range from 17 to 28 nm. The NPs' agglomerated shape and average particle size of 47–74 nm was observed by SEM. VSM studies show that the 100 mL extract-based sample exhibited the highest saturation magnetization of 65.71 emu g⁻¹. The band gap was measured using the Kubelka–Munk technique and increased from 2.261 to 2.475 eV with increasing extract volume. This study confirms that orange fruit extract can effectively synthesize nanoparticles of cobalt ferrite.